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Loss of Biodiversity in Livestock
Domestic animals make a major contribution to human requirements for food in the form of meat, milk, milk products, eggs, fibre, fertiliser for crops as well as draught power. This major contribution is made by some 4,500 breeds drawn from 40 or more animal species. These breeds, developed over the past 12,000 years, represent the remaining pool of genetic diversity from which future demands must be met. However, they currently are dying out at a rate of six breeds per month. Latest information suggests that 30 percent of the world’s breeds are at risk of extinction.
These breeds commonly possess valuable traits such as adaptation to harsh conditions, including tolerance of parasitic and infectious diseases, drought and poor quality feed. They are being replaced in both developed and developing countries by a few high production breeds which, to be successful, require high inputs, skilled management and comparatively benign environments.
Within the agricultural context, animal biodiversity is the genetic variability (or diversity) between breeds and within breeds of the same species. Within agricultural systems biological diversity is often referred to as “Agrobiodiversity”.
There is still a large diversity in the genotypes of livestock species. This results from natural selection, reproduction in isolation, and from breeding for specific purposes. However, agrobiodiversity is declining due to an increase in communication, changed demand for livestock products and services, and innovations in the livestock sector resulting in more uniform conditions for livestock.
This results from changes in the environment and therefore of genotype – environment interactions and natural selection. Investments are made to protect livestock from harsh conditions, feeding is improved and diseases are controlled with curative and preventative measures. Locally this results in a gradual change in genetic composition. Globally, the result is a reduction in agrobiodiversity. This process takes place in all livestock production systems.
Global decline in genetic diversity is also the result of the use of increased numbers of livestock from a small number of selected breeds. Changes in the productive environment create opportunities for use of exotic breeds where many years of selection has concentrated on production characteristics. Through replacement and cross-breeding the local variation in genetic composition initially increases but decreases as the characteristics of the local breeds are lost over time. The number of highly productive breeds is relatively small. Technical innovations in transport, communication and reproduction (hatcheries, AI, embryo transfer) facilitate the use of these few breeds on a world-wide basis and their representation in the livestock population is increasing.
The import of exotic breeds can result in activities within the livestock sector that are uneconomic and/or have a negative impact on the environment. In many cases these activities are subsidised or otherwise provided for by development programmes. Measurements to support livestock production include for example:
More recently alternative approaches have been promoted, but usually at a small scale, e.g.:
The focus in the earlier approaches is on changing the environment to create opportunities for exotic breeds to be productive. In the more recent approach the focus is on accepting certain constraints of the environment and using breeds that can cope with these constraints. A parallel can been seen in the crop sector: chemical pest control versus selection on disease resistance.
Maintenance of the genetic diversity of livestock is therefore important.
The demand for milk, meat and eggs is developing faster than that for other livestock products and services such as hair, wool, animal traction and transport (where demand is usually decreasing). In the competition for scarce resources, species and breeds renowned for these more traditional products and services (camels, donkeys, horses, buffalo, elephants, llamas, yaks, wool sheep, etc.) are at the loosing end, also in the resource driven farming systems. Gradually nomads and farmers replace traditional species and breeds by species and breeds that have a greater productivity and therefore higher economic value in the short term. As a result, population sizes of these traditional breeds are decreasing, their management gets poorer and performances decline. Some of these breeds have been included in breeding programmes aiming at safeguarding them for the purpose of genetic diversity. However, these programmes are costly and can only survive when external parties show an interest in keeping them.
The impact of the environment on the genetic composition of breeds and the use of certain species is highest in the extensive grazing and the mixed farming grazing systems. Because of the large diversity in ecological settings there is a large diversity in genetic composition amongst the breeds in these systems. Many of these systems make use of environments that are marginal for other uses but rely for certain periods of the year on environments that have a higher potential (e.g. flood plains and mountain valleys). Increased competition for the use of these areas is a threat for these extensive livestock systems and so for the global genetic diversity of livestock species.
The present high-input high-output industrial agricultural systems are characterised by the use of high levels of fertilisers and good quality feed concentrates. Within these systems veterinary treatment with drugs for preventive and clinical use is sometimes practised at a high level. Environmental problems and resistance against drugs can create conditions for animal production in which higher levels of feed conversion efficiency and disease resistance are required. The conservation of biodiversity is required as sources of genes, which are necessary as an insurance against changes in production circumstances, or the threat of a new disease. Animal production geneticists world-wide are searching for genes which influence the production, quality of products, and the health or reproduction traits of animals. In this search, crosses between breeds with extreme characteristics play an important role. This type of crossbreeding requires a high level of biodiversity within the species. The existence of many local breeds contribute to such a biodiversity.
Results of experience and research show that greater levels of agrobiodiversity can:
Rød Dansk Malkerace bull
From the above it can be seen that there is considerable concern about the diversity of livestock, and this is indeed recognised as a major problem. However, who is to take on the responsibility and burden of maintaining livestock diversity? Can developing countries afford it? For example, in Denmark, original Danish landraces are maintained through government (and EU) support. The breeding of seed stock for the Danish Landrace in Denmark is carried out on a national scale in herds registered, supervised, and approved by the National Committee for Pig Production.
It is not however, the commercial farmers who are keeping many of these rarer livestock breeds, it is the hobby/part-time farmers. The Golden Guernsey Goat is now very rare in its original island home but is maintained by hobbyists and part-time farmers on the UK mainland. The same is true of many other rare breeds of livestock.
Having been maintained in this way by non-commercial interests, some rare livestock breeds are now receiving interest for human health, environmental and other reasons. But without the interest of hobbyists in keeping these breeds, there is the significant danger of losing potentially valuable qualities.
The two ancient breeds of sheep – Soay and Old Norwegian – have meat that is now recognised as being of particularly high quality. Unlike the meat from other breeds the majority of the fat is located in the kidney region and around the gut. Since the taste is related to the fat, and these breeds have very little fat in the meat, the taste is more reminiscent of roe-deer and reindeer than mutton. The wool of both breeds is also of high quality. The production is ecologically oriented since the animals usually graze outside on land with no surplus fertilizer and the animals normally get very little surplus feeding, if any.
If maintenance of livestock diversity is a true concern for the world community a strategy must be drawn-up to maintain them, but one cannot expect that farmers in developing countries should refrain from changing their breeds for the sake of mankind, especially when the use of “improved” breeds confers advantages in the form of increased productivity.
Thrupp, L. A., 1998. Linking Biodiversity and Agriculture: Challenges and Opportunities for Sustainable Food Security. World Resources Institute. 72 pages.
Mason, I. L., 1988. World Dictionary of Livestock Breeds. Wallingford: CAB International. 348 pages.
Alderson, L., and R. Dowling, 1995. Rare Breeds. London: Bulfinch Press. 144 pages.
Domestic Animal Diversity Information System DAD-IS.
Oklahoma State University. 1999. Breeds of Livestock.
The above article has been reprinted with permission from the Food and Agriculture Organization (FAO) of the United Nations (UN) – see Loss of Biodiversity in Livestock. © FAO 2006, found at www.virtualcentre.org/in/dec/toolbox/indust/lossagbi.htm
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